runtime: don't enable heap randomization if MSAN or ASAN is enabled

MSAN and ASAN do confusing things to the memory layout, which are likely
to conflict with heap base randomization, so if they are enabled,
ignore randomizedHeapBase64.

We already didn't turn it on when TSAN was enabled.

Change-Id: I41e59dfc33d8bb059c208a9595442571fb31eea3
Reviewed-on: https://go-review.googlesource.com/c/go/+/704856
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Michael Knyszek <[email protected]>
Auto-Submit: Roland Shoemaker <[email protected]>

Author: rolandshoemaker

src/runtime/export_test.go

@@ -9,7 +9,6 @@ package runtime
 import (
 	"internal/abi"
 	"internal/goarch"
-	"internal/goexperiment"
 	"internal/goos"
 	"internal/runtime/atomic"
 	"internal/runtime/gc"
@@ -1156,7 +1155,7 @@ func CheckScavengedBitsCleared(mismatches []BitsMismatch) (n int, ok bool) {
 		getg().m.mallocing--
 	})
 
-	if goexperiment.RandomizedHeapBase64 && len(mismatches) > 0 {
+	if randomizeHeapBase && len(mismatches) > 0 {
 		// When goexperiment.RandomizedHeapBase64 is set we use a series of
 		// padding pages to generate randomized heap base address which have
 		// both the alloc and scav bits set. Because of this we expect exactly

src/runtime/malloc.go

@@ -349,7 +349,7 @@ const (
 
 	// randomizeHeapBase indicates if the heap base address should be randomized.
 	// See comment in mallocinit for how the randomization is performed.
-	randomizeHeapBase = goexperiment.RandomizedHeapBase64 && goarch.PtrSize == 8 && !isSbrkPlatform
+	randomizeHeapBase = goexperiment.RandomizedHeapBase64 && goarch.PtrSize == 8 && !isSbrkPlatform && !raceenabled && !msanenabled && !asanenabled
 
 	// randHeapBasePrefixMask is used to extract the top byte of the randomized
 	// heap base address.